Plate fin heat exchanger with curved expansion tubes



A rifi M, 3%? J- R. HAYDEN PLATE FIN HEAT EXCHANGER WITH CURVED EXPANSION TUBES Filed May 11, 1965 2 Sheets-Sheet 1 April 11, 1967 J. R. HAYDEN 3,313,344

PLATE FIN HEAT EXCHANGER WITH CURVED EXPANSION TUBES Filed May 11. 1965 2 Sheets-Sheet 2 IN VEN TOR.

BY .70/71? 1?. Hayden 67 United States Patent Oflice 3,313,344 PLATE FEW HEAT EXCHANGER WITH CURVED EXPANSION TUBES John Robert Hayden, Lockport, N.Y., assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed May 11, 1965, Ser. No. 454,839 Claims. (Cl. 165-166) This invention relates to heat exchangers and more particularly to regenerative type heat exchangers designed to operate under high temperature conditions.

Stacked plate heat exchangers of this general type are disclosed in the United States Patent No. 2,526,135 granted Oct. 17, 1950, in the names of J. C. Holmes, H. F. May and J. R. Hayden. This patent discloses an excellent heat exchange structure but such a structure is nevertheless subject to expansion and contraction problems encountered under some conditions of usage. In that structure, plates and fins are brazed together in one solid unit with the stacked plates and fins being joined by brazing. Heavy gage sheet material is joined with light gage material in forming the stack and the areas of joinder often exhibit leakage due to the differential expansion and contraction encountered in those areas.

An object of the present invention is to provide an improved heat exchanger of the regenerative type in which expansion and contraction is absorbed in the exchanger structure with substantial elimination of stresses and strains heretofore due to that expansion and contraction occurring as the exchanger metal work alternately heats and cools.

A feature of the present invention is a heat exchanger comprising a stack of inter-iorly and exteriorly finned and substantially flat heat exchanger sections which sections are relatively movable with at least one end of each section having curved tubes connecting that end to a manifold.

The above and other features of the invention will now be described in detail in the specification and then pointed out more particularly in the appended claims.

In the drawings:

FIGURE 1 is an elevation view of a gas-air heat exchanger with portions broken away better to express the invention;

FIGURE 2 is a view looking in the direction of the arrows 22 in FIGURE 1;

FIGURE 3 is a perspective view, enlarged somewhat, of one end portion of a heat exchanger section such as shown in the stack of such sections in FIGURE 2, a portion of one header or manifold being included; and

FIGURE 4 is a further enlarged perspective view of portions of two adjacent sections as employed in the stack of multiple sections of FIGURE 2.

FIGURES 1 and 2 show a casing having a corrugated bottom side 12 as shown in FIGURE 2 and a top side 14 which is likewise corrugated but not shown as such in the drawings. Manifolding is formed with the aid of the casing 10 at opposite sides of the heat exchanger and on each end this manifolding includes a partially cylindrical tank or header 16 or 18. Each end of the tank 16 or 18 is closed by means of a circular plate such as the plate 19. The header 16 at one side of the heat exchanger has a flared duct with an elongated opening 20 and the cylindrical header 18 has a different form of flared duct with an opening 22.

In the casing 10 beneath the opening 20 and its surrounding flange structure 24 is a rectangular opening 26. Above the cylindrical header 18 and in the casing 10 is an opening 28 surrounded by a flange 3%.

Inside the casing 10 is located a multiplicity of substantially fiat finned heat exchanger sections 40. These sections are stacked in contactual relation and rest in the corrugations of the bottom and top walls 12 and 14 of the casing 10.

FIGURE 3 shows one end of a single heat exchanger section 40 which is made in one unit insofar as the stacked plates, fins and the tubes serving those particular plates are concerned. Each of the heat exchanger sections 40 includes two plates 42 and 44 flanged at their peripheries to cooperate with an interiorly located corrugated fin 46 whereby passages are formed for one fluid passing between the plates. The apices of the interior corrugated plate 46 may or may not be solidly joined to the plates 42 and 44. The opposite and exterior sides of each section 40 constitute corrugated fins 48 and 50 which are brazed solidly to the two plates 42 and 44 respectively.

At opposite edges of each heat exchanger section the plates 42 and 44 are flanged and joined together in such a way as to form connect-ions with multiple tubes 52. These tubes of a given section are all curved or so arranged as to form connections between the passages leading through the particular section 40 and the cylindrical header 16. Preferably the curved tubes 52 at each end of a given section lie in a single plane and tubes at opposite ends of a section all lie in a single plane.

The header 18 is similarly connected by means of tubes which are curved as are the tubes 52 but which are not shown in the drawings except for those tubes 54 defining the outline of the nest of tubes.

In operation, air to be heated is forced through the opening 20 into the header 16 from which the air flows through the tubes 52 to the multiplicity of sections 40. This air is guided by the interior corrugated fins 46 and then is discharged by way of curved tubes leading to the header 18 and from which the heated air is discharged by way of the opening 22. Hot gas is caused to flow countercurrently and out of contact with the air being heated by introducing the hot gas through the opening 28 leading to around the tubes at that side of the heat exchanger and then along the corrugated sheets 48 and 50 of all the sections for discharge between the opposite tubes 52 and out by way of the opening 26.

From the above, it will be seen that the sections 40 readily move with respect to each other in the planes between the contacting apices of the sheets 48 and 50 thereby eliminating any differential expansion or contraction which may occur in the various portions of the heat exchanger. The curvature of the tubes connecting these sections with the two headers 16 and 18 permits independent movement of the sections without straining the tube connections and although the sections 40 are retained by the corrugations in the top and bottom walls 14 and 12 of the casing 10, suflicient space is provided between the adjacent flanges of the sections 40 to permit expansion of the plates.

Because of this construction, any gage material may be used throughout the stack and the heat exchanger is capable of serving under high temperature conditions without ruptures occurring due to either general or localized expansion or contraction of the parts.

I claim:

1. A heat exchanger comprising a stack of plate sections, manifolding at opposite sides of said stack separately to conduct two fluids, each section being a unit including two plates, an interior fin and exterior fins, said two plates and interior fin defining passages for one of said fluids, said exterior fins defining passages for the other of said fluids, the exterior fins of each of said sections being free to move relatively with respect to the exterior fins of at least one adjacent section, said manifolding at one of said sides of said stack including curved tubes connecting said passages for said one of said fluids to a common opening, and a casing surrounding said Patented Apr. 11, 1967 I) curved tubes and connected as a common conduit connected to said passages for the said other fluid.

2. A heat exchanger comprising a stack of plate sections, manifolding at opposite sides of said stack separately to conduct two fluids, each section being separately constructed and including two corrugated plates, an interior fin and exterior fins, said two plates and fins being corrugated, said two plates and interior fin defining passages for one of said fluids, said exterior fins cooperating with adjacent plate sections for defining passages for the other of said fluids, the exterior fins of each of said sections being free to move with respect to the exterior fins of at least one adjacent section, said manifolding at each of said sides of said stack including curved tubes connecting said passages for said one of said fluids to a common opening, and the casing surrounding said curved tubes at each side of said stack connected as a common conduit for said passages for the said other fluid.

3. A heat exchanger such as set forth in claim 1, said fins being corrugated to present ridges and grooves extending all in one direction.

4. A heat exchanger such as set forth in claim 1, the

ridges of the exterior fins of each of said sections having site ports for the admission and discharge of one gaseous fluid, a header at opposite sides of and integral with said casing and adjacent said opposite ports, a stack of separately constructed plate sections interposed in said casing between said ports and headers, each of said plate sections having curved tubes connecting it to said headers and exterior corrugated plates fixed as integral parts to the said plate section, the corrugations of each of the exterior plates of all of said sections extending in one direction and slidable with relation to an adjacent section, and the arrangement being such that said one fluid may flow between said sections and a second fluid may flow from one of the said headers and through each of said sections to the other of said headers.

References Cited by the Examiner UNITED STATES PATENTS 1,795,537 3/1931 Barske 122--510 2,576,213 11/1951 Chausson 165-166 2,858,112 10/1958 Gerstung 165-166 3,024,003 3/1962 Speca et al. 165166 3,100,140 8/1963 Ashley et al 165116 X 5 ROBERT A. OLEARY, Primary Examiner.

T. W. STREULE, Assistant Examiner. 

1. A HEAT EXCHANGER COMPRISING A STACK OF PLATE SECTIONS, MANIFOLDING AT OPPOSITE SIDES OF SAID STACK SEPARATELY TO CONDUCT TWO FLUIDS, EACH SECTION BEING A UNIT INCLUDING TWO PLATES, AN INTERIOR FIN AND EXTERIOR FINS, SAID TWO PLATES AND INTERIOR FIN DEFINING PASSAGES FOR ONE OF SAID FLUIDS, SAID EXTERIOR FINS DEFINING PASSAGES FOR THE OTHER OF SAID FLUIDS, THE EXTERIOR FINS OF EACH OF SAID SECTIONS BEING FREE TO MOVE RELATIVELY WITH RESPECT TO THE EXTERIOR FINS OF AT LEAST ONE ADJACENT SECTION, SAID MANIFOLDING AT ONE OF SAID SIDES OF SAID STACK INCLUDING CURVED TUBES CONNECTING SAID PASSAGES FOR SAID ONE OF SAID FLUIDS TO A COMMON OPENING, AND A CASING SURROUNDING SAID CURVED TUBES AND CONNECTED AS A COMMON CONDUIT CONNECTED TO SAID PASSAGES FOR THE SAID OTHER FLUID. 